The present invention relates to reverse-osmosis apparatus and more particularly to an energy conservation pumping system for use in the desalinization of sea water by reverse osmosis ultrafiltration.
It has previously been recognized that the desalinization of sea water by reverse osmosis or ultrafiltation involves considerable wastage of energy if the concentrated by-product (brine) is discharged at the high pressure required for reverse osmosis without employing some means to recover the energy latent in that flow. Energy recovery schemes are described for example in the U.S. Pat. No. 4,354,939 issued on Oct. 19, 1982 to Kurt M. Pohl and in the article entitled "Energy Recovery For Small Reverse-Osmosis Systems" by Jeffrey C. Eid and Melvin E. Mattson.
While the systems described in these prior publications may provide for the recovery of otherwise lost energy, they have not proven cost effective in actual practice for a variety of reasons. Principal among the difficulties encountered in these prior art systems is the need to provide pumps which will pump sea water at high pressure or which will pump sea water at a high ambient pressure though required only to provide only a small differential pressure. As will be understood by those skilled in the art, these requirements are not easily met by readily available standard components.
Among the several objects of the present invention may be noted the provision of novel apparatus for desalinizing sea water; the provision of desalinization apparatus which does not require the conventional pumping of sea water at high pressure; the provision of pressure reverse osmosis apparatus which is energy efficient; the provision of reverse osmosis apparatus which does not require the operation at high ambient pressure of pumps providing relatively small pressure differentials; the provision of such apparatus which is highly reliable and cost effective and which is of relatively simple and inexpensive construction. Other objects and features will be in part apparent and in part pointed out hereinafter.